Hoist push button control



Dec; 30, 1969 G. R. SANTOS 3,487,280

HOIST PUSH BUTTON CONTROL Filed March 17, 1967 I 2 Sheets-Sheet 2INVENTOR. G. R. SANTOS ATTORNEYS United States Patent F 3,487,280 HOISTPUSH BUTTON CONTROL Gerard R. Santos, Levittown, Pa., assignor to EatonYale & Towne Inc., Cleveland, Ohio, a corporation of Ohio Filed Mar. 17,1967, Ser. No. 623,915 Int. Cl. H02p 1/40, 1/00, 3/00 US. Cl. 318-267Claims ABSTRACT OF THE DISCLOSURE My invention relates to motor operatedhoists.

As may be appreciated, there is a considerable demand for motor operatedhoists that an operator can control through the actuation of pushbuttons. There are in use many hoists that are controlled in that way,but due to the particular requirements of hoist operation, the pushbuttons often have made it necessary to equip the hoist with controlmechanism that is quite complex and costly. In some cases, the controlsdo not offer the best performance. Through the novel concept of myinvention, it will be possible to achieve extremely satisfactoryoperation of a hoist while utilizing push button control. Moreover, thatcan be done through means that are relatively low in cost and thatactually are quite simple.

In my invention, I equip a hoist with a motor switch that may be of ausual type, together with a yielding connection through which controlmeans will act to move the motor switch. The operator of the hoist willactuate the control means, as by push buttons, for controlling thelifting and lowering movements of the hoist. There are further means formoving the switch, and those means will be effective through yielding ofthe yielding connection to move the switch independently of the controlmeans. More particularly, the further means will be limit means thatmove the switch to neutral position incidental to a limit operation ofthe hoist.

As a feature of my invention, I equip a hoist with a pair of solenoidsthat will move a switch from a neutral position to opposed positions foreffecting lifting and lowering movements of the hoist. The solenoids arevery well adapted to be controlled through push buttons and enable me toconstruct an effective hoist control requiring no complex circuits. As amore particular feature, I utilize a spring through which a solenoidnormally will act to control the switch. The spring may yield when theswitch is moved by hoist limit means, so that the limit means cannotoverstress the solenoid when overriding the control that may be appliedby the solenoid.

I have thus outlined rather broadly the more important features of myinvention in order that the detailed description thereof that followsmay be better understood, and in order that my contribution to the artmay be better appreciated. There are, of course, additional features ofmy invention that will be described hereinafter and which will form thesubject of the claims appended hereto. Those skilled in the art willappreciate that the concept upon which my disclosure is based mayreadily be utilized as a basis for the designing of other structures forcarrying out the several purposes of my invention. It is important,therefore, that the claims be regarded as including such equivalentconstructions as do not depart from the spirit and scope of myinvention, in

3,487,280 Patented Dec. 30, 1969 order to prevent the appropriation ofmy invention by those skilled in the art.

In the drawings:

FIG. 1 shows a perspective view of a hoist that utilizes my invention.

FIG. 2 shows a diagrammatic view of my invention.

FIG. 3 shows a longitudinal section of the switch shaft and springassembly.

FIG. 4 shows a cross-section on the line 4-4 in FIG. 3, the assemblybeing in neutral position.

FIG. 5 is a section like FIG. 4 but shows the assembly in normal liftingcontrol position.

FIG. 6 is similar to FIG. 5 but illustrates the yielding of the springwhen the limit control overrides normal lifting control.

FIG. 7 illustrates the yielding when the normal control is in loweringposition.

Referring now more particularly to FIG. 1 of the drawings, I show mynovel control 10 utilized on an electric hoist 11 having a frame 12 thatis equipped with a support hook 13, and a motor 14 for operating a loadchain 15. Those skilled in the art will understand that the motor 14 mayoperate in opposed directions to effect lifting and lowering movementsof the load chain 15, there being suitable gearing (not shown) throughwhich the motor acts. A limit member 16, a part of which can be seen inFIG. 1, will limit the operations of the hoist, and I shall refer inmore detail to the limit member 16 as my description proceeds.

Referring again to FIG. 1, I mount on the hoist 11 a motor switch 17having an operating shaft 18 that can rotate from a neutral position ineither direction to energize the motor 14 in a corresponding direction.Preferably, the switch 17 is equipped with a centering spring 19, showndiagrammatically in FIGURE 2, applying pressure to a cam 19a on switchshaft 18 so as to press the switch shaft 18 toward neutral position. Forpurposes of disclosure FIGURE 2 also shows switch 17 equipped with acontact arm 17a that the shaft 18 will rotate from neutral position toengage either of two contacts 17b, so as to complete a correspondingdirectional circuit that will connect motor 14 through lines 14a to asource of power 14b. I believe that it will be unnecessary to describemotor switch 17 in further detail because that switch may be of astandard type. It is merely necessary here to know that the switchoperating shaft 18 can be rotated to opposed positions effecting liftingand lowering movements of the load chain 15, the shaft 18 in neutralposition stopping the operation of the chain. Merely to facilitate mydescription, I shall assume that switch shaft 18 is placed in liftingposition when rotated counterclockwise, as viewed in FIG. 1.

In my novel control 10, I utilize a pair of solenoids 20, 21 mounted onthe hoist frame 12, as through a bracket 22, that normally will controlthe rotation of the switch shaft 18. Power for the solenoids 20, 21 maybe supplied through a transformer 60 that is connected to source 14]),FIGS. 1 and 2, and the operator of the hoist may energize the solenoidsby depressing corresponding push buttons 61, 62. The armature 23 of eachsolenoid 20, 21 is connected to one end of a chain 24 that engages asprocket 25, so that one solenoid when energized will rotate thesprocket in each direction. Solenoid 20 will effect counterclockwiserotation and therefore I may term it a lifting solenoid, and solenoid 21a lowering solenoid.

The sprocket 25 is integrally secured to a sleeve portion 26 of acontrol part 27, best shown in FIG. 3, that is mounted to rotaterelatively to the switch operating shaft 18. The control part 27 forms aportion of an assembly including a coil spring 28, and a mounting part29 that is integrally secured to the end of switch shaft 18, as by ascrew 30. I prefer to utilize a bushing 31 that keys a stem portion 32of mounting part 29 to a portion 33 of switch shaft 18, those portions32 and 33 being squared, as indicated in dotted lines in FIG. 4, tocoact with a corresponding square opening in bushing 31. Control part 27and its sprocket 25 then may rotate on the outer surface of bushing 31,with the friction preferably reduced through roller bearings 34.

Coacting with the coil spring 28, the control part 27 has inner andouter cylindrical walls 35 and 36, FIGS. 3 and 4, while mounting part 29has cylindrical walls 37, 38 each arranged just inwardly of thecorresponding Wall 35 or 36 on part 27. Between inner wall 35 on part 27and outer wall 38 on part 29 is a circular space in which coil spring 28is assembled.

As well shown in FIG. 4, the outer walls 36, 38 on control part 27 andmounting part 29 are formed with clearance openings 39, 40, one end ofthose openings forming stop surfaces 41, 42 for an angular end portion43 on coil spring 28. Similarly, inner walls 35, 37 have clearanceopenings 44, 45 forming stop surfaces 46, 47 in opposed relation tosurfaces 41, 42 and coacting with the inner spring end 48. Coil spring28 is so tensioned that its end portions 43, 48 will act between theopposed stop surfaces 41, 42 and 46, 47, tending to prevent any relativerotation between the control part 27 and mounting part 29. At thosetimes when the spring 28 yields, there naturally will be rotation in onedirection or the other between the parts 27 and 29, while the springends 43, 48 move away from certain stop surfaces in the clearanceopenings, as may be seen in FIGS. 6 and 7. Actually, the coil spring 28that I utilize in my invention will have strength sufiicient to holdparts 27, 29 in a predetermined relation to one another during normaloperation of the hoist. Normally, therefore, parts 27 and 29 will rotatein unison, as from the FIG. 4 position to the FIG. position, so that thesolenoids 20, 21 will fully control the rotation of the switch shaft 18.

I shall refer to FIG. 2 of the drawings while describing further meansthat will rotate switch shaft 18. Thus, I show diagrammatically at 50 inFIG. 2 a usual type of limit control including the limit member 16, towhich I already have referred in connection with FIG. 1. The limitmember 16 is arranged below a usual load wheel 51 through which thehoist motor operates the load chain 15, and is mounted at a medial pointfor tilting about a pivot 52 on the hoist frame. I show limit member 16connected through link means 53 and a crank 54 to the switch operatingshaft 18 so that limit member 16 by tilting may move the motor switch17. The load portion 55 and slack portion 56 of the load chain extendfrom the load wheel 51 downwardly and when operating will move freely inopenings in opposed portions of limit member 16. Load portion 55 ofchain 15 is equipped with a load hook 57, while slack portion 56 isanchored at 58 to the hoist frame.

The limit arrangement that I have just described is not new, and thosepersons skilled in the art will understand that load chain 15 whenmoving to an upper limit position will cause the load hook 57 to engagethe limit member 16 and to tilt it counterclockwise, as viewed in FIG.2. When chain 15 moves to a lower limit position, its slack portion 56Will engage a portion of limit member 16 so as to tilt it clockwise.That tilting of limit member 16 in either direction will move shaft 18to neutral so as to stop the operation of motor 17 and chain 15. Shouldthere be some overtravel of chain 15, that is, past a limit position,the tilting of member 16 will move switch shaft 18 past neutral so as toreverse the hoist motor, causing chain 15 to move back to limitposition. That naturally will enable member 16 and shaft 18 to moveagain to neutral position.

I now call attention to the fact that the limit control 50 may operatethrough yielding of the coil spring 28, so as to rotate switch shaft 18independently of the normal control that is applied through thesolenoids 20,

21. Let us assume as an example that limit control 50 acts whilesolenoid 20 holds switch shaft 18 in lifting. position. In that positionof shaft 18, control part 27 and mounting part 29 will be in thepositions 27a, 29a, shown in FIG. 5, having been rotated from theneutral FIG. 4 position. Now, upon lifting limit operation of the limitcontrol 50, the mounting part 29 will rotate with switch shaft 18 backto neutral position as shown in FIG. 6, while coil spring 28 yields sothat control part 27 may remain in its position 27a. The lowering limitcontrol operation will be substantially the same, though naturally beingin directions opposed to those I have described, and with spring 28yielding while control part 27 is held in position 27b as shown in FIG.7.

I have already mentioned the fact that overtravel of the load chain 15will cause switch shaft 18 to rotate past neutral, thereby reversing thehoist motor. When shaft 18 rotates in that way, the coil spring 28 canyield farther as I shall explain. Referring to FIGS. 5 and 6, it will beseen that the clearance openings 39, 40 and 44, 45 are considerablywider than is necessary to allow the spring ends 43, 48 to move When thelimit control merely rotates mounting part 29 to neutral position. Inthe particular example shown, there merely need be a movement ofapproximately 45 between each spring end 43, 48 and its correspondingopening 39, 45. However, as also shown, each clearance opening actuallyallows approximately clearance. Thus, the spring ends 43, 48, can movefarther, enabling coil spring 28 to yield while the limit controlrotates mounting part 29 beyond its neutral position to a motorreversing position.

It will now be understood that my invention will enable the operator ofa hoist to utilize push buttons so as to apply normal control to themovements of a hoist, while also enabling a limit control to actelfectively while overriding the push button control.

However, to fully appreciate my invention, it is necessary to realizethat the limit control cannot overstress the normal control. That isimportant because the operator of a hoist frequently will attempt tohold the normal control in actuated position after the limit control operates. In my invention, when that happens, the normal control mayremain in actuated position and the limit control cannot force it towardneutral position. Thus, when the normal control comprises a solenoid,the operator cannot injure or destroy the solenoid through a continuedapplication of power when the limit control operates.

Further, by utilizing solenoids I am able to control the movements of ahoist through means that are quite simple, while well adapted to beactuated through push buttons. Also, I achieve control that is extremelyeffective and that will very well meet the requirements of hoistoperation. I believe, therefore, that the considerable value of myinvention will be understood, and that its merits will be appreciated bythose persons skilled in the art.

I now claim:

1. In a hoist having a load member and a motor for operating the loadmember, a switch for said motor, movable control means connected to theswitch for moving said switch whereby to control the operation of thehoist load member by said motor, yielding means forming a connectingpart between the control means and the motor switch and through whichsaid control means normally act to control the movements of said switchto motor actuating and to neutral positions, limit means actingindependently of said control means for moving the switch to a neutralposition incidental to an operation of the load member, and saidyielding means yieldmg so that said limit means cannot overstress thecontrol means while moving the switch independently of said controlmeans.

2. A construction as set forth in claim 1, including opposed stopsurfaces against which said yielding means press on said switch and onsaid control means, and said yielding means having strength sufficientthat its pressure against said surfaces normally will move the switch inunison with the control means.

3. A construction as set forth in claim l, in which said control meansinclude a solenoid that acts through said yielding means, and means toenergize said solenoid for moving said switch, and said yielding meanshaving strength sufficient normally to move the switch in unison withthe solenoid.

4. In a hoist having a load member and a motor for operating the loadmember, a switch movable to opposed positions actuating the motor toeffect lifting and lowering movements of the load member, a pair ofsolenoids, means connecting each solenoid to said switch so as to beeffective when energized to move the switch to one of said opposedpositions, means for selectively energizing one solenoid or the othersolenoid whereby to control the operation of the load member, furthermeans positively connected to said switch and effective by moving theswitch for positively overriding the control applied through thesolenoids, and said means that connect each solenoid to the switchcomprising a yielding portion that will yield so that said further meanscannot overstress the solenoids when overriding the solenoid control.

5. A construction as set forth in claim 4, in which a spring forms saidyielding portion of the connecting means, and including stop surfacesbetween which said spring acts relatively to the switch and solenoidswhereby to press the switch toward a predetermined relation to thesolenoids.

6. In a hoist having a load member and a motor for operating the loadmember, a switch having an operating member movable from a neutralposition to opposed positions actuating the motor to effect lifting andlowering movements of the load member, a control part mounted formovement relatively to the switch operating member, means for movingsaid control part, a spring connecting the control part and the switchoperating member and through Which said part may move said operatingmember to control the lifting and lowering movements of the hoist loadmember, limit means connected to the switch operating member andactuated by the load member positively to move said operating member toneutral position incidental to an operation of the load member, and saidspring effective by yielding to enable the limit means to actindependently of the movements of the control part.

7 A construction as set forth in claim 6, in which said spring hasstrength sufficient normally to hold the switch operating member inpredetermined relation to said control part.

8. A construction as set forth in claim 6, in which said means formoving the control part comprise a pair of solenoids, and means forenergizing said solenoids selectively to move the control part inopposed directions.

9. In a hoist having a load member operated through the actuation of amotor, and a switch equipped with a shaft that is rotatable from aneutral position in opposed directions to positions actuating the motorto effect lifting and lowering movements of the load member, a controlpart mounted for rotation on said switch shaft, a spring having opposedends engaging the switch shaft and a control part and connecting saidshaft and part for rotation normally with one another, a pair ofsolenoids connected to the control part for rotating said part inopposed directions, push buttons for energizing selectively one solenoidor the other solenoid whereby to control the rotation of the switchshaft, limit means connected to the switch shaft and effective to rotatesaid shaft independently of the control part to neutral position wherebyto override the solenoid control incidental to a movement of the hoistload member to a limit position, and said spring yielding so that thelimit means when overriding the solenoid control cannot overstress thesolenoids.

10. A construction as set forth in claim 9, in which said spring is acoil spring mounted in the axis of the switch shaft, said shaft and saidcontrol part having stop surfaces between which the spring ends act topress said shaft toward a normal relation to said part, and said stopsurfaces moving through yielding of said spring to enable said limitmeans to rotate the switch shaft in either direction from its normalrelation to the control part.

References Cited UNITED STATES PATENTS 8/1941 Collins 318-466 1/1951Townsley et al 318466 U.S. c1. X.R. 31 8446, 468

